The American Journal of Sports Medicine http://ajs.sagepub.com/
Functional Testing Differences in Anterior Cruciate Ligament Reconstruction Patients Released Versus Not Released to Return to Sport Stephanie W. Mayer, Robin M. Queen, Dean Taylor, Claude T. Moorman III, Allison P. Toth, William E. Garrett, Jr and Robert J. Butler Am J Sports Med published online April 13, 2015 DOI: 10.1177/0363546515578249 The online version of this article can be found at: http://ajs.sagepub.com/content/early/2015/04/13/0363546515578249
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Functional Testing Differences in Anterior Cruciate Ligament Reconstruction Patients Released Versus Not Released to Return to Sport Stephanie W. Mayer,* MD, Robin M. Queen,*yz PhD, Dean Taylor,* MD, Claude T. Moorman III,* MD, Allison P. Toth,* MD, William E. Garrett Jr,* MD, PhD, and Robert J. Butler,*y DPT, PhD Investigation performed at Duke University Medical Center, Durham, North Carolina, USA Background: No standardized return-to-activity or sport guidelines currently exist after anterior cruciate ligament (ACL) reconstruction. Isokinetic testing and unilateral hop testing, which have construct validity, are often used to make the determination of when a patient is ready to return to sport. Neither of these measures has been reported to be predictive of subsequent injuries. Purpose: To compare the performance on 2 functional tests of ACL reconstruction patients released to return to activity versus those who have not been released based on clinical impairment measures. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 98 patients were examined by the treating orthopaedic surgeon 6 months after ACL reconstruction for traditional impairment measures, including swelling, range of motion, strength, and graft stability. After this examination, all subjects completed the functional testing, consisting of the Functional Movement Screen (FMS) and the Lower Quarter Y Balance Test (YBT-LQ), by an experienced tester who was blinded to the results of the clinical examination. On the basis of the clinical examination, all patients were grouped as being ready to return to sport or not being ready. Performance on the functional tests, as measured by overall performance and side-to-side asymmetry, was compared between the 2 groups using independent-samples t tests (P \ .05). Results: No difference existed between the groups with regard to the descriptive characteristics, with the exception that the group not cleared was younger (21.0 6 7.4 years) than the group that was cleared (25.6 6 13.2 years). Performance on the YBT-LQ revealed that no differences existed between groups when examining reach symmetry for any of the reach directions. In addition, no differences were found between groups when looking at the average reach score normalized to limb length for either the surgical or nonsurgical leg. Patients in the cleared group exhibited a similar score on the FMS (12.7 6 2.9) compared with the noncleared group (12.8 6 2.7). Similarly, no differences were observed for the number of asymmetries; however, both groups averaged 1 asymmetry during the testing. Conclusion: Clinical impairment measures do not appear to be related to measured functional ability. Performance on both functional tests, the FMS and YBT-LQ, at 6 months would suggest that the typical patient in both groups would be at a greater risk of lower extremity injury, based on currently published research. Keywords: Lower Quarter Y Balance Test; Functional Movement Screen; objective measures; ACL
z
Address correspondence to Robin M. Queen, PhD, Duke University Medical Center, DUMC 102916, Durham, NC 27705, USA (email: [email protected]). *Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina, USA. y Michael W. Krzyzewski Human Performance Research Laboratory, Duke University Medical Center, Durham, North Carolina, USA. One or more of the authors has declared the following potential conflict of interest or source of funding: R.J.B. is a research consultant for Functional Movement Systems LLC, who fabricates and distributes the Functional Movement Screen.
Anterior cruciate ligament (ACL) tears are a common injury in sports medicine, and it is estimated that 125,000 to 200,000 ACL reconstructions are performed each year.3,23 Many patients who undergo reconstruction were participating in organized sports at a high level at the time of injury.§ It has been reported that between 49% and 92% of patients return to some level of competitive sports by 12 to 13 months after surgery, with as few as 33% of patients returning to their preinjury level of
The American Journal of Sports Medicine, Vol. XX, No. X DOI: 10.1177/0363546515578249 Ó 2015 The Author(s)
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References 4, 5, 14, 19-21, 23, 25, 27, 29, 39-42.
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activity.1,2,15,22,23 With the limited number of athletes returning to full sport participation, it is important to note that the retear rate after ACL reconstruction is between 9.6% and 25%.|| It is known that muscle imbalance and weakness occur after ACL reconstruction and can persist for up to 2 years after surgery.13,31 Despite this information, athletes are often released to return to sport between 6 and 12 months after reconstruction.3,13,31 The topic of return to sport criteria has been popular in the literature, and there are no current universal guidelines that have shown a clear advantage in returning an athlete to previous level of sport, decreasing retear rates, or preserving long-term joint health.3,42 Based on a systematic review of all studies citing their return to sport criteria, the possible measures include time since surgery, effusion, gait, strength, graft laxity, and traditional functional testing such as single-legged hop, single-legged squat, active straight leg raise, in-line lunge, deep squat, shuttle run, side-step, resisted knee extension, resisted knee flexion, and leg press. The most often used criterion for return to sport is time since surgery (60%).3,4 Only 15% of studies used another subjective criterion, while 13% reported using an objective criteria.4 The lack of consensus on return-to-sport criteria was discussed by Petersen and Zantop,33 who included in their commentary the need for a ‘‘return to sports score’’ that includes physical examination and functional testing that could be validated to guide physicians on the appropriateness for the patient to safely return to sports. Movement pattern assessment as well as proprioceptive control and dynamic functional capacity of patients who suffer an ACL tear as well as those after ACL reconstruction has begun to be investigated and has been reported to be abnormal in both patient groups.9,10 Two tests that have been suggested to assess movement, proprioception, and dynamic ability in a clinically efficient way are the Functional Movement Screen (FMS; Functional Movement Systems LLC) and the Lower Quarter Y Balance Test (YBT-LQ; Move2Perform LLC). The FMS was developed to assess functional movement patterns with a series of tests that require both mobility and stability.6,9,10,19,24 The FMS consists of 7 activities, including a deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push up, and rotary stability. Specific scoring of these tests has been outlined in prior studies and texts.9,10,26 Although these activities are not purely lower-body activities, the goal of this series of tests is to determine abnormal movement patterns and deficits in both strength and mobility of the musculoskeletal system. Since most activities are performed as part of a closed-chain system, coordinated movement relies on the control of several muscle groups. Weakness in part of the chain can cause abnormal and possibly unsafe compensatory action in another group to complete the task.9,10 Deficits in each portion of the test can identify specific muscle groups that lack strength, range of motion, neuromuscular control, or coordination.9,10 Poor performance
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References 1, 5, 8, 11, 15, 18, 20, 23, 25, 32, 37, 39, 40.
on the FMS test has been shown to correlate with increased risk of injury in players in the National Football League, firefighters, and military recruits in training.6,19,24 Since the implications of a low score on this test are predictive of who is at risk for lower extremity injury, the results of postoperative testing after ACL reconstruction could be of use in determining who has regained the strength and control to safely return to sport. The YBT-LQ was developed as a relatively simple and reproducible measure of balance and dynamic control.34 The YBT-LQ is derived from the Star Excursion Balance Test (SEBT) and uses a standardized testing kit that improves the efficiency of the testing setup. Dynamic balance, as scored on the SEBT, has been shown to be a reliable measure of dynamic balance, and poor performance or asymmetrical performance has been associated with an elevated risk of lower extremity injury.6,12,34,35 The YBTLQ is tested for each leg separately. The patient stands in a single-legged stance in the center of the testing apparatus and with the other leg pushes a reach indicator in the anterior, posteromedial, and posterolateral direction in relation to the stance foot. This is repeated for the operative and nonoperative leg, and the overall reach distances are averaged and normalized to limb length as well assessed for side-to-side differences, which are calculated for each direction.34 Unilateral performance assessments, such as the YBT-LQ, are important in postoperative patient populations in which unilateral deficits can be masked during performance of bilateral tasks. Given that there is no current consensus on the best criteria for safe return to sport, the purpose of this study was to investigate the usefulness of the FMS and the YBT-LQ as an adjunct to physical examination and other clinical objective measures to determine patients’ readiness to return to sport. Through this study, we aimed to determine if a difference existed for either the FMS or YBT-LQ when comparing patients who were clinically deemed ready to return to sport and those who were not. The results of this study could provide insight into persistent proprioceptive and neuromuscular control deficits that may not be evident on clinical examination. The patients’ individual deficiencies could then be addressed using a tailored therapy intervention. In addition, this information could be used to create return-to-sport guidelines for surgeons by combining clinical data with this relatively simple, efficient, and affordable functional test battery, which could be administered during a clinic visit.
METHODS Institutional review board approval was obtained for a retrospective chart review analysis of data collected during standard clinical care that is stored in a clinical database examining changes in patient function after surgical interventions. Standardized postoperative rehabilitation and evaluation protocols approved by the treating physician were used for all patients in this study. All of the data collected for the study were part of standard postoperative care after ACL reconstruction.
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Figure 1. Descriptive images of the 7 individual tests of the Functional Movement Screen. A search by Current Procedural Terminology (CPT) code was conducted to identify all patients who underwent a primary ACL reconstruction between September 2010 and March 2012 at our institution. Patients were included in this study if they were older than 12 years; had a traumatic ACL tear confirmed by physical examination, imaging, and intraoperative findings; underwent ACL reconstruction; and had complete follow-up and functional testing with the YBT-LQ and FMS between 5 and 9 months postoperatively. This time point was selected as it is a common range when patients are discharged from rehabilitation and allowed to return to sports. Exclusion criteria were age younger than 13 years, incomplete clinical follow-up or functional testing, multiligamentous knee injury, previous nonoperatively treated ACL tear, and severe cognitive, neurologic, or muscular conditions prohibiting standard rehabilitation protocols. Additional exclusion criteria related to postoperative outcomes were complications at any time point including arthrofibrosis, painful or prominent hardware, infections, and further knee injuries. Demographic data including age, sex, height, and weight at the time of surgery and any previous surgeries were recorded. In addition, the mechanism of injury and previous sport played were noted. All individuals enrolled in the study were examined clinically at a standard postoperative appointment. This visit occurred between 5 and 9 months when decisions regarding return to sport begin to have relevance in the plan of care for the athlete. Specific study-related data that were collected during the visit were numeric pain scores (0-10 scale), presence of an effusion, range of motion, Lachman and pivot-shift testing. In addition to these measures, graft laxity was objectively measured with a KT-1000
arthrometer (MEDmetric), and isokinetic quadriceps strength was tested with a Cybex device (Cybex International) and recorded as absolute strength and as a percentage of the well leg. Quadriceps strength values were not collected on all subjects because of clinical time constraints and the distance the patient traveled for the surgery; however, these data were examined when available. Data were available for all patients who completed rehabilitation at the surgical facility. At the same visit, the FMS (Figure 1) and the YBT-LQ (Figure 2) were administered. The FMS testing included the deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability/push up, and rotary stability tests as outlined by Cook et al9,10 (see the Video Supplement to this article). The total composite score as well as the number of asymmetries between the operative and nonoperative leg were calculated. YBT-LQ testing data were recorded for anterior, posteromedial, and posterolateral reaches for both the operative and nonoperative legs.34 The average normalized reach score for each leg was calculated as well as the reach symmetry for each reach direction. Subjects were grouped based on whether they had been cleared by clinical criteria alone at the time of the examination. The decision of cleared versus not cleared was made by the treating orthopaedic surgeon and was based on clinical findings as well as objective measures including KT-1000 arthrometer and isokinetic strength testing. Patients were cleared to return to sports if they had progressed through the standard rehabilitation program and on clinical examination had no effusion, range of motion within 5° of the contralateral leg, a Lachman test with less than 5 mm of translation and a firm endpoint, a negative pivot-shift test, a KT-1000 arthrometer test within
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Figure 2. Examples of the 3 different reach directions completed during the Lower Quarter Y Balance Test (A, anterior; B, posteromedial; C, posterolateral). 5 mm of the contralateral limb, and isokinetic testing demonstrating no or mild quadriceps strength deficits. Each patient was analyzed individually when making this decision, taking into account the planned level of participation and sport to which the patient was returning. Therefore, at the discretion of the treating surgeon, patients could be cleared for return to their desired sport despite not meeting all of the criteria outlined above. The cleared and not-cleared groups were compared to determine if statistically significant differences existed between the 2 groups with regard to their FMS and YBT-LQ scores. In addition, the number of asymmetries on the FMS and the magnitude of reach asymmetry on the YBT-LQ were examined. A 2tailed unpaired t test was used for statistical analysis, with the level of significance set at P \ .05.
RESULTS Based on the inclusion and exclusion criteria that were defined, a total of 98 patients were included in this study. The sport being played when the injury occurred varied, with 34 soccer, 18 basketball, 14 American football, 10 fitness, 9 skiing, 4 lacrosse, 4 volleyball, and 1 each for tennis, track, golf, cricket, and hockey were reported. The time of the testing occurred at 6.5 6 1.3 months after surgery. Of the 98 patients, 37 patients had been cleared (YES) to return to sport at the time of their FMS and YBT-LQ testing, and 61 had not been released (NO). Of the patients, 81.6% underwent primary ACL reconstruction alone, while 13.3% underwent an additional meniscal repair at the time of their ACL reconstruction. Of the patients, 60.4% received a hamstring autograft alone, 12.5% received a bone–patellar tendon–bone autograft alone, 6.3% received an allograft, and 20.8% received a combination of auto- and allograft. Demographics of the
clinical outcomes and descriptive statistics between groups are presented in Table 1. The mean weight in the YES group (74.33 6 15.14 kg) was not different from that of the NO group (74.44 6 14.72 kg; P = .96). The mean height was not different between the 2 groups (YES: 1.74 6 0.10 m, NO: 1.74 6 0.09 m; P = .87). The mean age was statistically different between the 2 groups, with the YES group being significantly older (25.6 6 13.2 years) than the NO group (21.0 6 7.4 years; P = .03).
Clinical Testing Physical examination and clinical data of the YES group indicated that 32 of 37 patients had no effusion, and the remaining 5 patients had persistent grade 1 effusions. All patients in the YES group had symmetric extension to the nonsurgical leg, and no patient was noted to have more than a 1° flexion contracture. All patients in the YES group had flexion equal or better than the nonsurgical leg. All patients in the YES group had less than 5 mm of anterior translation and a firm endpoint on the Lachman test. No patient in the YES group was noted to have a pivot shift. The mean pain score was 0.42 6 0.84 out of 10 (range, 0-3 on the visual analog scale). The average sideto-side difference on KT-1000 testing was 1.79 6 1.35 mm (range, 0-5 mm) in the YES group. During isokinetic quadriceps testing, 4 patients were noted to have equal or better strength compared with the contralateral side, 13 with mild deficit, 3 with moderate deficit, and 1 with significant deficit in the YES group. Physical examination data of the NO group indicated that 10 of 61 patients had persistent grade 1 effusion; all others had no effusion. Eight patients in the NO group were noted to have clinically significant flexion contractures (1 patient at 15°, 1 patient at 10°, and 6 patients at 5°). All other patients in the NO group had a range of
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TABLE 1 Clinical Examination Data for Cleared Versus Not-Cleared Groupsa
TABLE 2 Lower Quarter Y Balance Test Data for Cleared Versus Not-Cleared Groups P Value
Height, m, mean 6 SD Cleared Not cleared Weight, kg, mean 6 SD Cleared Not cleared Age, y, mean 6 SD Cleared Not cleared KT-1000 testing, mm, mean 6 SD Cleared Not cleared Current pain (visual analog scale), mean 6 SD Cleared Not cleared ACL hamstring autograft, % Cleared Not cleared ACL hamstring combination auto- and allograft, % Cleared Not cleared Concomitant meniscal repair, % Cleared Not cleared Effusion grade 1, % Cleared Not cleared
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.87 1.74 6 0.10 1.74 6 0.09 .96 74.3 6 15.1 74.4 6 14.7 .03 25.6 6 13.2 21.0 6 7.4 .64 1.79 6 1.35 1.64 6 1.26 .73 0.42 6 0.84 0.30 6 0.65 .54
Mean 6 SD Anterior difference, cm Cleared Not cleared Posterolateral difference, cm Cleared Not cleared Posteromedial difference, cm Cleared Not cleared Y balance test composite surgical leg, % leg length Cleared Not cleared Y balance test composite nonsurgical leg, % leg length Cleared Not cleared
P Value .327
4.4659 6 3.62709 3.7315 6 3.70455 .705 4.0000 6 3.00194 4.2593 6 3.61958 .273 4.5341 6 3.08673 3.8519 6 3.01667 .877 93.0953 6 8.38820 93.3695 6 8.94535 .906 95.4481 6 9.33564 95.2257 6 9.12311
59.5 65.5 .27
TABLE 3 Functional Movement Screen (FMS) Data for Cleared Versus Not-Cleared Groups
21.6 13.1 .76
Mean 6 SD
11.4 13.5 .93 13.5 16.3
a
ACL, anterior cruciate ligament.
motion equal to their contralateral leg. All but 2 patients in the NO group had less than 5 mm of anterior translation with a firm endpoint on the Lachman test. These 2 patients had between 5 and 10 mm of translation with a firm endpoint. No patient had a pivot shift. The mean pain score was 0.30 6 0.65 out of 10 (range, 0-3) in the NO group. The mean side-to-side difference on KT-1000 arthrometer testing was 1.64 6 1.26 mm (range, 0-4.5 mm) in the NO group. During isokinetic quadriceps testing, 4 patients were noted to have equal or better strength compared with the nonsurgical leg, 20 had mild deficits, 12 had moderate deficits, and 1 had a significant deficit in the NO group.
Functional Assessments: YBT-LQ and FMS Scores The mean composite score of the YBT-LQ for the surgical leg in the YES group (93.10 6 8.39) was not statistically different from that of the NO group (93.37 6 8.95; P = .88). Similarly, the mean composite YBT-LQ score of the nonsurgical leg in the YES group (95.45 6 9.34) was no different from that of the NO group (95.23 6 9.12; P = .91). There was also a similar percentage of patients who fell at or below the established cut point of 94.0% leg length
FMS composite score Cleared Not cleared Number of FMS asymmetries Cleared Not cleared
P Value .873
12.7250 6 2.87329 12.8222 6 2.71602 .740 1.0263 6 0.94402 0.9524 6 1.03482
on the surgical side in the YES group (54.1%, 20/37) compared with the NO group (49.2%, 30/61). Analysis of the difference between surgical and nonsurgical sides for the individual reach directions (anterior, posterolateral, and posteromedial) on the YBT-LQ is displayed in Table 2. There was no statistically significant difference in reach asymmetry for any of the independent reach directions of the YBT-LQ between groups (anterior, P = .33; posterolateral, P = .71; and posteromedial, P = .27). There was no statistically significant difference in the average FMS composite score between the YES (12.73 6 2.87) and NO groups (12.82 6 2.72; P = .873). There was also a similar percentage of patients who fell at or below the established cut point of 14 in the YES group (67.6%, 25/37) compared with the NO group (59.0%, 36/61). In addition, there was not a statistically significant difference in the number of asymmetries on the FMS between groups (YES: 1.03 6 0.94, NO: 0.95 6 1.03; P = .74) (Table 3).
DISCUSSION Return-to-activity/sport decisions are an important part of the rehabilitation process as patients integrate back to sports
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and ultimately to the presurgery level of function, particularly after ACL reconstruction. Traditionally, return-to-sport decision making has relied primarily on patient interview and clinical examination. Recent research has identified movement-based screens that may be able to assist in identifying athletes at risk for future injury. Movement assessments have yet to be consistently integrated into the clinical decision-making process because of the lack of understanding of how these tools further our knowledge of appropriate return-to-sport criteria. The results of this study suggest that return-to-sport decision making based on clinical examination and surgeon opinion alone does not differentiate patients with poor levels of neuromuscular function that place athletes at an elevated risk for future injury. The results of the study suggests that many patients who meet traditional clinical criteria for return to sport including time since surgery, effusion, range of motion, graft laxity, and quadriceps strength still have functional and neuromuscular deficits that may put them at risk for further lower extremity injury. Poor neuromuscular control and biomechanical aberrancies have been implicated in ACL rupture as well as retears.13,16,17,32,38 Based on the results of this study, there is no significant difference in scoring on the FMS test between the patients who were clinically cleared for return to sporting activities without restriction and those who were not. Scores for both the cleared (12.73 6 2.9) and not-cleared group (12.82 6 2.7) are below the injury predictive threshold of 14 and well below the normative value of 15.7 6 1.9 published by Schneiders et al36 in uninjured populations. This comparison between prior research and the current study would suggest that at the time of testing, these athletes were deficient in dynamic control and therefore at an increased risk for injury.19,36 Similarly, there was no statistical difference between the YBT-LQ composite or individual reach direction distances between patients who were cleared to return to sport and those who were not cleared. However, performance on the YBT-LQ displayed low competency and reach asymmetry levels that were below normative levels as well as below established cut points (\94.0% leg length) that have been previously associated with an elevated risk of injury.7,35 The observation of reach asymmetry across both groups may suggest that movement deficits may have existed before the initial ACL rupture and thus may have been associated with the initial injury. The lack of difference in FMS and YBT-LQ outcomes between the 2 groups suggests that a routine clinical examination may not pick up neuromuscular control deficits, which may be compensated for and nonobserved during clinical evaluation but which may be contributing to an abnormal movement pattern, placing the limb at risk for reinjury. With high retear and reinjury rates and no ideal postoperative assessment tool as yet, there is room for continued investigation into options to create an objective guide for safe return to sport. A recent systematic review concluded that of the 264 articles reviewed, only 13% included an objectively measured criterion other than postoperative time as part of their return-to-sport guidelines.3 The most commonly reported criteria included some combination of
muscle strength analysis via isokinetic testing or evaluation of quadriceps atrophy, knee effusion, range of motion, single-legged hop testing, stability on the Lachman test, pivot shift, or KT-1000 arthrometer (MEDmetric), and validated questionnaires such as Knee Injury and Osteoarthritis Outcome Score or Knee Self Efficacy Score.3 Recently, it was shown that patients who were cleared for return to sports based on postoperative time and clinical criteria had persistent limb asymmetry in single-legged hop height and vertical ground-reaction forces compared with age-matched controls.28 In addition, in another recent article, patients who did not pass return-to-sport criteria (time greater than 6 months, isokinetic quadriceps strength testing, single-legged hop, crossover hop, triple hop, and timed hop as well as self-reported outcomes measures) had significantly different gait behaviors detectable on force plates and with 3-dimensional motion analysis.13 Other biomechanical studies have evaluated posture and strength32 and valgus loading17 during jump landing for prediction of injury or reinjury of the ACL. These studies found significant differences in neuromuscular control causing altered knee position during landing in patients who suffered an ACL injury, further strengthening the idea of postural stability, flexibility, and neuromuscular control as key components of full rehabilitation after ACL reconstruction. These previous results are similar to what is being reported in the current study, which indicates that many patients who were clinically cleared for return to sports still lack complete motor control and coordination. An advantage of the functional testing used in the current study is that this functional assessment is inexpensive and can be used in any office setting compared with highly technical equipment needed for biomechanical analysis through force plates and 3-dimensional motion capture. To date, no battery of tests has been shown to be effective in reducing future injury rates after ACL reconstruction, which makes this an area of high interest.30 The present study is the first to our knowledge to use the FMS and YBT-LQ tests to detect deficits in neuromuscular control and side-to-side asymmetries after ACL reconstruction as an adjunct to traditional clinical examinations and testing. The current study does have limitations. Although the clinical and rehabilitation protocols were the same across the study population, there were three surgeons involved in performing surgery and clinical examinations, several graft types were used, and multiple physical therapists supervised therapy. Thus, there was heterogeneity in the subjective nature of the decision making pre-, intra-, and postoperatively because of surgeon bias as well as differences in expectations attributed to age, comorbidities, and sport participation. In addition, although the data were collected prospectively according to our department’s protocol, the retrospective nature of the data review carries some inherent bias. An additional limitation is the differences in age between the cleared and noncleared group, which may be resolved in a larger scale study. It has been suggested that younger patients recover more quickly than older patients do, and thus the fact that the cleared group was older than the noncleared group would tend to
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be in contrast to current clinical impression. The difference in age may also be attributed to different clearing standards associated with an older patient population who may be returning to a less intense level of competition/ activity. While both populations were considered to be young adults in nature and thus the difference in biologic age likely has minimal effect on the tissue-healing abilities associated with recovery time, it would be expected that the activity level differences between these age groups would be associated with different levels of reinjury risk and thus would be an important factor in return-to-play decision making.38 Finally, this initial study would have benefitted from a larger sample size to normalize some of the descriptive statistics associated with the patient samples. Future directions of this work will include following this cohort for a longer period of time to better examine reinjury rates and determine if the FMS and YBT-LQ normative values correlate with risk of reinjury in patients after ACL reconstruction. Ultimately, we aim to determine criteria using both clinical and functional testing values to develop an ideal set of return-to-sports criteria.
CONCLUSION There was no difference in FMS or YBT-LQ test scores in patients after ACL reconstruction who were clinically deemed appropriate for return to unrestricted activity based on clinical criteria. The use of the FMS and YBTLQ allow for additional tools that could be used quickly and efficiently in an office setting to give more information on the movement abilities of each patient.
A Video Supplement for this article is available in the online version or at http://ajsm.sagepub.com/supplemental.
REFERENCES 1. Ardern CL, Webster KE, Taylor NF, Feller JA. Return to sport following anterior cruciate ligament reconstruction surgery: a systematic review and meta-analysis of the state of play. Br J Sports Med. 2011;45(7):596-606. 2. Ardern CL, Webster KE, Taylor NF, Feller JA. Return to the preinjury level of competitive sport after anterior cruciate ligament reconstruction surgery: two-thirds of patients have not returned by 12 months after surgery. Am J Sports Med. 2011;39(3):538-543. 3. Barber-Westin SD, Noyes FR. Factors used to determine return to unrestricted sports activities after anterior cruciate ligament reconstruction. Arthroscopy. 2011;27(12):1697-1705. 4. Barber-Westin SD, Noyes FR. Objective criteria for return to athletics after anterior cruciate ligament reconstruction and subsequent reinjury rates: a systematic review. Phys Sportsmed. 2011;39(3):100-110. 5. Brophy RH, Schmitz L, Wright RW, et al. Return to play and future ACL injury risk after ACL reconstruction in soccer athletes from the Multicenter Orthopaedic Outcomes Network (MOON) group. Am J Sports Med. 2012;40(11):2517-2522. 6. Butler RJ, Contreras M, Burton LC, Plisky PJ, Goode A, Kiesel K. Modifiable risk factors predict injuries in firefighters during training academies. Work. 2013;46(1):11-17.
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7. Butler RJ, Southers C, Gorman PP, Kiesel KB, Plisky PJ. Differences in soccer players’ dynamic balance across levels of competition. J Athl Train. 2012;47(6):616-620. 8. Cascio BM, Culp L, Cosgarea AJ. Return to play after anterior cruciate ligament reconstruction. Clin Sports Med. 2004;23(3):395-408, ix. 9. Cook G, Burton L, Hoogenboom B. Pre-participation screening: the use of fundamental movements as an assessment of function—part 1. N Am J Sports Phys Ther. 2006;1(2):62-72. 10. Cook G, Burton L, Hoogenboom B. Pre-participation screening: the use of fundamental movements as an assessment of function—part 2. N Am J Sports Phys Ther. 2006;1(3):132-139. 11. Czuppon S, Racette BA, Klein SE, Harris-Hayes M. Variables associated with return to sport following anterior cruciate ligament reconstruction: a systematic review. Br J Sports Med. 2014;48(5):356-364. 12. de Noronha M, Franca LC, Haupenthal A, Nunes GS. Intrinsic predictive factors for ankle sprain in active university students: a prospective study. Scand J Med Sci Sports. 2013;23(5):541-547. 13. Di Stasi SL, Logerstedt D, Gardinier ES, Snyder-Mackler L. Gait patterns differ between ACL-reconstructed athletes who pass return-tosport criteria and those who fail. Am J Sports Med. 2013;41(6):13101318. 14. Ekstrand J. A 94% return to elite level football after ACL surgery: a proof of possibilities with optimal caretaking or a sign of knee abuse? Knee Surg Sports Traumatol Arthrosc. 2011;19(1):1-2. 15. Gobbi A, Francisco R. Factors affecting return to sports after anterior cruciate ligament reconstruction with patellar tendon and hamstring graft: a prospective clinical investigation. Knee Surg Sports Traumatol Arthrosc. 2006;14(10):1021-1028. 16. Hewett TE, Di Stasi SL, Myer GD. Current concepts for injury prevention in athletes after anterior cruciate ligament reconstruction. Am J Sports Med. 2013;41(1):216-224. 17. Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study. Am J Sports Med. 2005;33(4):492-501. 18. Jang SH, Kim JG, Ha JK, Wang BG, Yang SJ. Functional performance tests as indicators of returning to sports after anterior cruciate ligament reconstruction. Knee. 2014;21(1):95-101. 19. Kiesel K, Plisky PJ, Voight ML. Can serious injury in professional football be predicted by a preseason functional movement screen? N Am J Sports Phys Ther. 2007;2(3):147-158. 20. Kvist J. Rehabilitation following anterior cruciate ligament injury: current recommendations for sports participation. Sports Med. 2004;34(4):269-280. 21. Laboute E, Savalli L, Puig P, et al. Analysis of return to competition and repeat rupture for 298 anterior cruciate ligament reconstructions with patellar or hamstring tendon autograft in sportspeople. Ann Phys Rehabil Med. 2010;53(10):598-614. 22. Langford JL, Webster KE, Feller JA. A prospective longitudinal study to assess psychological changes following anterior cruciate ligament reconstruction surgery. Br J Sports Med. 2009;43(5):377-381. 23. Lentz TA, Zeppieri G Jr, Tillman SM, et al. Return to preinjury sports participation following anterior cruciate ligament reconstruction: contributions of demographic, knee impairment, and self-report measures. J Orthop Sports Phys Ther. 2012;42(11):893-901. 24. Lisman P, O’Connor FG, Deuster PA, Knapik JJ. Functional movement screen and aerobic fitness predict injuries in military training. Med Sci Sports Exerc. 2013;45(4):636-643. 25. McCullough KA, Phelps KD, Spindler KP, et al. Return to high schooland college-level football after anterior cruciate ligament reconstruction: a Multicenter Orthopaedic Outcomes Network (MOON) cohort study. Am J Sports Med. 2012;40(11):2523-2529. 26. Minick KI, Kiesel KB, Burton L, Taylor A, Plisky P, Butler RJ. Interrater reliability of the functional movement screen. J Strength Cond Res. 2010;24(2):479-486. 27. Mohammadi F, Salavati M, Akhbari B, Mazaheri M, Mohsen Mir S, Etemadi Y. Comparison of functional outcome measures after ACL reconstruction in competitive soccer players: a randomized trial. J Bone Joint Surg Am. 2013;95(14):1271-1277.
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28. Myer GD, Martin L Jr, Ford KR, et al. No association of time from surgery with functional deficits in athletes after anterior cruciate ligament reconstruction: evidence for objective return-to-sport criteria. Am J Sports Med. 2012;40(10):2256-2263. 29. Myer GD, Paterno MV, Ford KR, Quatman CE, Hewett TE. Rehabilitation after anterior cruciate ligament reconstruction: criteria-based progression through the return-to-sport phase. J Orthop Sports Phys Ther. 2006;36(6):385-402. 30. Narducci E, Waltz A, Gorski K, Leppla L, Donaldson M. The clinical utility of functional performance tests within one-year post-ACL reconstruction: a systematic review. Int J Sports Phys Ther. 2011;6(4):333-342. 31. Palmieri-Smith RM, Thomas AC, Wojtys EM. Maximizing quadriceps strength after ACL reconstruction. Clin Sports Med. 2008;27(3):405424, vii-ix. 32. Paterno MV, Schmitt LC, Ford KR, et al. Biomechanical measures during landing and postural stability predict second anterior cruciate ligament injury after anterior cruciate ligament reconstruction and return to sport. Am J Sports Med. 2010;38(10):1968-1978. 33. Petersen W, Zantop T. Return to play following ACL reconstruction: survey among experienced arthroscopic surgeons (AGA instructors). Arch Orthop Trauma Surg. 2013;133(7):969-977. 34. Plisky PJ, Gorman PP, Butler RJ, Kiesel KB, Underwood FB, Elkins B. The reliability of an instrumented device for measuring components of the star excursion balance test. N Am J Sports Phys Ther. 2009;4(2):92-99.
35. Plisky PJ, Rauh MJ, Kaminski TW, Underwood FB. Star Excursion Balance Test as a predictor of lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006;36(12):911-919. 36. Schneiders AG, Davidsson A, Horman E, Sullivan SJ. Functional movement screen normative values in a young, active population. Int J Sports Phys Ther. 2011;6(2):75-82. 37. Shah VM, Andrews JR, Fleisig GS, McMichael CS, Lemak LJ. Return to play after anterior cruciate ligament reconstruction in National Football League athletes. Am J Sports Med. 2010;38(11):2233-2239. 38. Shelbourne KD, Gray T, Haro M. Incidence of subsequent injury to either knee within 5 years after anterior cruciate ligament reconstruction with patellar tendon autograft. Am J Sports Med. 2009;37(2):246251. 39. Shelbourne KD, Sullivan AN, Bohard K, Gray T, Urch SE. Return to basketball and soccer after anterior cruciate ligament reconstruction in competitive school-aged athletes. Sports Health. 2009;1(3):236241. 40. Simoneau GG, Wilk KE. The challenge of return to sports for patients post-ACL reconstruction. J Orthop Sports Phys Ther. 2012; 42(4):300-301. 41. Warner SJ, Smith MV, Wright RW, Matava MJ, Brophy RH. Sportspecific outcomes after anterior cruciate ligament reconstruction. Arthroscopy. 2011;27(8):1129-1134. 42. Yabroudi MA, Irrgang JJ. Rehabilitation and return to play after anatomic anterior cruciate ligament reconstruction. Clin Sports Med. 2013;32(1):165-175.
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Functional Testing Differences in Anterior Cruciate Ligament Reconstruction Patients Released Versus Not Released to Return to Sport Stephanie W. Mayer, Robin M. Queen, Dean Taylor, Claude T. Moorman III, Allison P. Toth, William E. Garrett, Jr and Robert J. Butler Am J Sports Med published online April 13, 2015 DOI: 10.1177/0363546515578249 The online version of this article can be found at: http://ajs.sagepub.com/content/early/2015/04/13/0363546515578249
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On behalf of: American Orthopaedic Society for Sports Medicine
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AJSM PreView, published on April 13, 2015 as doi:10.1177/0363546515578249
Functional Testing Differences in Anterior Cruciate Ligament Reconstruction Patients Released Versus Not Released to Return to Sport Stephanie W. Mayer,* MD, Robin M. Queen,*yz PhD, Dean Taylor,* MD, Claude T. Moorman III,* MD, Allison P. Toth,* MD, William E. Garrett Jr,* MD, PhD, and Robert J. Butler,*y DPT, PhD Investigation performed at Duke University Medical Center, Durham, North Carolina, USA Background: No standardized return-to-activity or sport guidelines currently exist after anterior cruciate ligament (ACL) reconstruction. Isokinetic testing and unilateral hop testing, which have construct validity, are often used to make the determination of when a patient is ready to return to sport. Neither of these measures has been reported to be predictive of subsequent injuries. Purpose: To compare the performance on 2 functional tests of ACL reconstruction patients released to return to activity versus those who have not been released based on clinical impairment measures. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 98 patients were examined by the treating orthopaedic surgeon 6 months after ACL reconstruction for traditional impairment measures, including swelling, range of motion, strength, and graft stability. After this examination, all subjects completed the functional testing, consisting of the Functional Movement Screen (FMS) and the Lower Quarter Y Balance Test (YBT-LQ), by an experienced tester who was blinded to the results of the clinical examination. On the basis of the clinical examination, all patients were grouped as being ready to return to sport or not being ready. Performance on the functional tests, as measured by overall performance and side-to-side asymmetry, was compared between the 2 groups using independent-samples t tests (P \ .05). Results: No difference existed between the groups with regard to the descriptive characteristics, with the exception that the group not cleared was younger (21.0 6 7.4 years) than the group that was cleared (25.6 6 13.2 years). Performance on the YBT-LQ revealed that no differences existed between groups when examining reach symmetry for any of the reach directions. In addition, no differences were found between groups when looking at the average reach score normalized to limb length for either the surgical or nonsurgical leg. Patients in the cleared group exhibited a similar score on the FMS (12.7 6 2.9) compared with the noncleared group (12.8 6 2.7). Similarly, no differences were observed for the number of asymmetries; however, both groups averaged 1 asymmetry during the testing. Conclusion: Clinical impairment measures do not appear to be related to measured functional ability. Performance on both functional tests, the FMS and YBT-LQ, at 6 months would suggest that the typical patient in both groups would be at a greater risk of lower extremity injury, based on currently published research. Keywords: Lower Quarter Y Balance Test; Functional Movement Screen; objective measures; ACL
z
Address correspondence to Robin M. Queen, PhD, Duke University Medical Center, DUMC 102916, Durham, NC 27705, USA (email: [email protected]). *Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina, USA. y Michael W. Krzyzewski Human Performance Research Laboratory, Duke University Medical Center, Durham, North Carolina, USA. One or more of the authors has declared the following potential conflict of interest or source of funding: R.J.B. is a research consultant for Functional Movement Systems LLC, who fabricates and distributes the Functional Movement Screen.
Anterior cruciate ligament (ACL) tears are a common injury in sports medicine, and it is estimated that 125,000 to 200,000 ACL reconstructions are performed each year.3,23 Many patients who undergo reconstruction were participating in organized sports at a high level at the time of injury.§ It has been reported that between 49% and 92% of patients return to some level of competitive sports by 12 to 13 months after surgery, with as few as 33% of patients returning to their preinjury level of
The American Journal of Sports Medicine, Vol. XX, No. X DOI: 10.1177/0363546515578249 Ó 2015 The Author(s)
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References 4, 5, 14, 19-21, 23, 25, 27, 29, 39-42.
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activity.1,2,15,22,23 With the limited number of athletes returning to full sport participation, it is important to note that the retear rate after ACL reconstruction is between 9.6% and 25%.|| It is known that muscle imbalance and weakness occur after ACL reconstruction and can persist for up to 2 years after surgery.13,31 Despite this information, athletes are often released to return to sport between 6 and 12 months after reconstruction.3,13,31 The topic of return to sport criteria has been popular in the literature, and there are no current universal guidelines that have shown a clear advantage in returning an athlete to previous level of sport, decreasing retear rates, or preserving long-term joint health.3,42 Based on a systematic review of all studies citing their return to sport criteria, the possible measures include time since surgery, effusion, gait, strength, graft laxity, and traditional functional testing such as single-legged hop, single-legged squat, active straight leg raise, in-line lunge, deep squat, shuttle run, side-step, resisted knee extension, resisted knee flexion, and leg press. The most often used criterion for return to sport is time since surgery (60%).3,4 Only 15% of studies used another subjective criterion, while 13% reported using an objective criteria.4 The lack of consensus on return-to-sport criteria was discussed by Petersen and Zantop,33 who included in their commentary the need for a ‘‘return to sports score’’ that includes physical examination and functional testing that could be validated to guide physicians on the appropriateness for the patient to safely return to sports. Movement pattern assessment as well as proprioceptive control and dynamic functional capacity of patients who suffer an ACL tear as well as those after ACL reconstruction has begun to be investigated and has been reported to be abnormal in both patient groups.9,10 Two tests that have been suggested to assess movement, proprioception, and dynamic ability in a clinically efficient way are the Functional Movement Screen (FMS; Functional Movement Systems LLC) and the Lower Quarter Y Balance Test (YBT-LQ; Move2Perform LLC). The FMS was developed to assess functional movement patterns with a series of tests that require both mobility and stability.6,9,10,19,24 The FMS consists of 7 activities, including a deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push up, and rotary stability. Specific scoring of these tests has been outlined in prior studies and texts.9,10,26 Although these activities are not purely lower-body activities, the goal of this series of tests is to determine abnormal movement patterns and deficits in both strength and mobility of the musculoskeletal system. Since most activities are performed as part of a closed-chain system, coordinated movement relies on the control of several muscle groups. Weakness in part of the chain can cause abnormal and possibly unsafe compensatory action in another group to complete the task.9,10 Deficits in each portion of the test can identify specific muscle groups that lack strength, range of motion, neuromuscular control, or coordination.9,10 Poor performance
||
References 1, 5, 8, 11, 15, 18, 20, 23, 25, 32, 37, 39, 40.
on the FMS test has been shown to correlate with increased risk of injury in players in the National Football League, firefighters, and military recruits in training.6,19,24 Since the implications of a low score on this test are predictive of who is at risk for lower extremity injury, the results of postoperative testing after ACL reconstruction could be of use in determining who has regained the strength and control to safely return to sport. The YBT-LQ was developed as a relatively simple and reproducible measure of balance and dynamic control.34 The YBT-LQ is derived from the Star Excursion Balance Test (SEBT) and uses a standardized testing kit that improves the efficiency of the testing setup. Dynamic balance, as scored on the SEBT, has been shown to be a reliable measure of dynamic balance, and poor performance or asymmetrical performance has been associated with an elevated risk of lower extremity injury.6,12,34,35 The YBTLQ is tested for each leg separately. The patient stands in a single-legged stance in the center of the testing apparatus and with the other leg pushes a reach indicator in the anterior, posteromedial, and posterolateral direction in relation to the stance foot. This is repeated for the operative and nonoperative leg, and the overall reach distances are averaged and normalized to limb length as well assessed for side-to-side differences, which are calculated for each direction.34 Unilateral performance assessments, such as the YBT-LQ, are important in postoperative patient populations in which unilateral deficits can be masked during performance of bilateral tasks. Given that there is no current consensus on the best criteria for safe return to sport, the purpose of this study was to investigate the usefulness of the FMS and the YBT-LQ as an adjunct to physical examination and other clinical objective measures to determine patients’ readiness to return to sport. Through this study, we aimed to determine if a difference existed for either the FMS or YBT-LQ when comparing patients who were clinically deemed ready to return to sport and those who were not. The results of this study could provide insight into persistent proprioceptive and neuromuscular control deficits that may not be evident on clinical examination. The patients’ individual deficiencies could then be addressed using a tailored therapy intervention. In addition, this information could be used to create return-to-sport guidelines for surgeons by combining clinical data with this relatively simple, efficient, and affordable functional test battery, which could be administered during a clinic visit.
METHODS Institutional review board approval was obtained for a retrospective chart review analysis of data collected during standard clinical care that is stored in a clinical database examining changes in patient function after surgical interventions. Standardized postoperative rehabilitation and evaluation protocols approved by the treating physician were used for all patients in this study. All of the data collected for the study were part of standard postoperative care after ACL reconstruction.
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Figure 1. Descriptive images of the 7 individual tests of the Functional Movement Screen. A search by Current Procedural Terminology (CPT) code was conducted to identify all patients who underwent a primary ACL reconstruction between September 2010 and March 2012 at our institution. Patients were included in this study if they were older than 12 years; had a traumatic ACL tear confirmed by physical examination, imaging, and intraoperative findings; underwent ACL reconstruction; and had complete follow-up and functional testing with the YBT-LQ and FMS between 5 and 9 months postoperatively. This time point was selected as it is a common range when patients are discharged from rehabilitation and allowed to return to sports. Exclusion criteria were age younger than 13 years, incomplete clinical follow-up or functional testing, multiligamentous knee injury, previous nonoperatively treated ACL tear, and severe cognitive, neurologic, or muscular conditions prohibiting standard rehabilitation protocols. Additional exclusion criteria related to postoperative outcomes were complications at any time point including arthrofibrosis, painful or prominent hardware, infections, and further knee injuries. Demographic data including age, sex, height, and weight at the time of surgery and any previous surgeries were recorded. In addition, the mechanism of injury and previous sport played were noted. All individuals enrolled in the study were examined clinically at a standard postoperative appointment. This visit occurred between 5 and 9 months when decisions regarding return to sport begin to have relevance in the plan of care for the athlete. Specific study-related data that were collected during the visit were numeric pain scores (0-10 scale), presence of an effusion, range of motion, Lachman and pivot-shift testing. In addition to these measures, graft laxity was objectively measured with a KT-1000
arthrometer (MEDmetric), and isokinetic quadriceps strength was tested with a Cybex device (Cybex International) and recorded as absolute strength and as a percentage of the well leg. Quadriceps strength values were not collected on all subjects because of clinical time constraints and the distance the patient traveled for the surgery; however, these data were examined when available. Data were available for all patients who completed rehabilitation at the surgical facility. At the same visit, the FMS (Figure 1) and the YBT-LQ (Figure 2) were administered. The FMS testing included the deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability/push up, and rotary stability tests as outlined by Cook et al9,10 (see the Video Supplement to this article). The total composite score as well as the number of asymmetries between the operative and nonoperative leg were calculated. YBT-LQ testing data were recorded for anterior, posteromedial, and posterolateral reaches for both the operative and nonoperative legs.34 The average normalized reach score for each leg was calculated as well as the reach symmetry for each reach direction. Subjects were grouped based on whether they had been cleared by clinical criteria alone at the time of the examination. The decision of cleared versus not cleared was made by the treating orthopaedic surgeon and was based on clinical findings as well as objective measures including KT-1000 arthrometer and isokinetic strength testing. Patients were cleared to return to sports if they had progressed through the standard rehabilitation program and on clinical examination had no effusion, range of motion within 5° of the contralateral leg, a Lachman test with less than 5 mm of translation and a firm endpoint, a negative pivot-shift test, a KT-1000 arthrometer test within
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Figure 2. Examples of the 3 different reach directions completed during the Lower Quarter Y Balance Test (A, anterior; B, posteromedial; C, posterolateral). 5 mm of the contralateral limb, and isokinetic testing demonstrating no or mild quadriceps strength deficits. Each patient was analyzed individually when making this decision, taking into account the planned level of participation and sport to which the patient was returning. Therefore, at the discretion of the treating surgeon, patients could be cleared for return to their desired sport despite not meeting all of the criteria outlined above. The cleared and not-cleared groups were compared to determine if statistically significant differences existed between the 2 groups with regard to their FMS and YBT-LQ scores. In addition, the number of asymmetries on the FMS and the magnitude of reach asymmetry on the YBT-LQ were examined. A 2tailed unpaired t test was used for statistical analysis, with the level of significance set at P \ .05.
RESULTS Based on the inclusion and exclusion criteria that were defined, a total of 98 patients were included in this study. The sport being played when the injury occurred varied, with 34 soccer, 18 basketball, 14 American football, 10 fitness, 9 skiing, 4 lacrosse, 4 volleyball, and 1 each for tennis, track, golf, cricket, and hockey were reported. The time of the testing occurred at 6.5 6 1.3 months after surgery. Of the 98 patients, 37 patients had been cleared (YES) to return to sport at the time of their FMS and YBT-LQ testing, and 61 had not been released (NO). Of the patients, 81.6% underwent primary ACL reconstruction alone, while 13.3% underwent an additional meniscal repair at the time of their ACL reconstruction. Of the patients, 60.4% received a hamstring autograft alone, 12.5% received a bone–patellar tendon–bone autograft alone, 6.3% received an allograft, and 20.8% received a combination of auto- and allograft. Demographics of the
clinical outcomes and descriptive statistics between groups are presented in Table 1. The mean weight in the YES group (74.33 6 15.14 kg) was not different from that of the NO group (74.44 6 14.72 kg; P = .96). The mean height was not different between the 2 groups (YES: 1.74 6 0.10 m, NO: 1.74 6 0.09 m; P = .87). The mean age was statistically different between the 2 groups, with the YES group being significantly older (25.6 6 13.2 years) than the NO group (21.0 6 7.4 years; P = .03).
Clinical Testing Physical examination and clinical data of the YES group indicated that 32 of 37 patients had no effusion, and the remaining 5 patients had persistent grade 1 effusions. All patients in the YES group had symmetric extension to the nonsurgical leg, and no patient was noted to have more than a 1° flexion contracture. All patients in the YES group had flexion equal or better than the nonsurgical leg. All patients in the YES group had less than 5 mm of anterior translation and a firm endpoint on the Lachman test. No patient in the YES group was noted to have a pivot shift. The mean pain score was 0.42 6 0.84 out of 10 (range, 0-3 on the visual analog scale). The average sideto-side difference on KT-1000 testing was 1.79 6 1.35 mm (range, 0-5 mm) in the YES group. During isokinetic quadriceps testing, 4 patients were noted to have equal or better strength compared with the contralateral side, 13 with mild deficit, 3 with moderate deficit, and 1 with significant deficit in the YES group. Physical examination data of the NO group indicated that 10 of 61 patients had persistent grade 1 effusion; all others had no effusion. Eight patients in the NO group were noted to have clinically significant flexion contractures (1 patient at 15°, 1 patient at 10°, and 6 patients at 5°). All other patients in the NO group had a range of
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TABLE 1 Clinical Examination Data for Cleared Versus Not-Cleared Groupsa
TABLE 2 Lower Quarter Y Balance Test Data for Cleared Versus Not-Cleared Groups P Value
Height, m, mean 6 SD Cleared Not cleared Weight, kg, mean 6 SD Cleared Not cleared Age, y, mean 6 SD Cleared Not cleared KT-1000 testing, mm, mean 6 SD Cleared Not cleared Current pain (visual analog scale), mean 6 SD Cleared Not cleared ACL hamstring autograft, % Cleared Not cleared ACL hamstring combination auto- and allograft, % Cleared Not cleared Concomitant meniscal repair, % Cleared Not cleared Effusion grade 1, % Cleared Not cleared
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.87 1.74 6 0.10 1.74 6 0.09 .96 74.3 6 15.1 74.4 6 14.7 .03 25.6 6 13.2 21.0 6 7.4 .64 1.79 6 1.35 1.64 6 1.26 .73 0.42 6 0.84 0.30 6 0.65 .54
Mean 6 SD Anterior difference, cm Cleared Not cleared Posterolateral difference, cm Cleared Not cleared Posteromedial difference, cm Cleared Not cleared Y balance test composite surgical leg, % leg length Cleared Not cleared Y balance test composite nonsurgical leg, % leg length Cleared Not cleared
P Value .327
4.4659 6 3.62709 3.7315 6 3.70455 .705 4.0000 6 3.00194 4.2593 6 3.61958 .273 4.5341 6 3.08673 3.8519 6 3.01667 .877 93.0953 6 8.38820 93.3695 6 8.94535 .906 95.4481 6 9.33564 95.2257 6 9.12311
59.5 65.5 .27
TABLE 3 Functional Movement Screen (FMS) Data for Cleared Versus Not-Cleared Groups
21.6 13.1 .76
Mean 6 SD
11.4 13.5 .93 13.5 16.3
a
ACL, anterior cruciate ligament.
motion equal to their contralateral leg. All but 2 patients in the NO group had less than 5 mm of anterior translation with a firm endpoint on the Lachman test. These 2 patients had between 5 and 10 mm of translation with a firm endpoint. No patient had a pivot shift. The mean pain score was 0.30 6 0.65 out of 10 (range, 0-3) in the NO group. The mean side-to-side difference on KT-1000 arthrometer testing was 1.64 6 1.26 mm (range, 0-4.5 mm) in the NO group. During isokinetic quadriceps testing, 4 patients were noted to have equal or better strength compared with the nonsurgical leg, 20 had mild deficits, 12 had moderate deficits, and 1 had a significant deficit in the NO group.
Functional Assessments: YBT-LQ and FMS Scores The mean composite score of the YBT-LQ for the surgical leg in the YES group (93.10 6 8.39) was not statistically different from that of the NO group (93.37 6 8.95; P = .88). Similarly, the mean composite YBT-LQ score of the nonsurgical leg in the YES group (95.45 6 9.34) was no different from that of the NO group (95.23 6 9.12; P = .91). There was also a similar percentage of patients who fell at or below the established cut point of 94.0% leg length
FMS composite score Cleared Not cleared Number of FMS asymmetries Cleared Not cleared
P Value .873
12.7250 6 2.87329 12.8222 6 2.71602 .740 1.0263 6 0.94402 0.9524 6 1.03482
on the surgical side in the YES group (54.1%, 20/37) compared with the NO group (49.2%, 30/61). Analysis of the difference between surgical and nonsurgical sides for the individual reach directions (anterior, posterolateral, and posteromedial) on the YBT-LQ is displayed in Table 2. There was no statistically significant difference in reach asymmetry for any of the independent reach directions of the YBT-LQ between groups (anterior, P = .33; posterolateral, P = .71; and posteromedial, P = .27). There was no statistically significant difference in the average FMS composite score between the YES (12.73 6 2.87) and NO groups (12.82 6 2.72; P = .873). There was also a similar percentage of patients who fell at or below the established cut point of 14 in the YES group (67.6%, 25/37) compared with the NO group (59.0%, 36/61). In addition, there was not a statistically significant difference in the number of asymmetries on the FMS between groups (YES: 1.03 6 0.94, NO: 0.95 6 1.03; P = .74) (Table 3).
DISCUSSION Return-to-activity/sport decisions are an important part of the rehabilitation process as patients integrate back to sports
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and ultimately to the presurgery level of function, particularly after ACL reconstruction. Traditionally, return-to-sport decision making has relied primarily on patient interview and clinical examination. Recent research has identified movement-based screens that may be able to assist in identifying athletes at risk for future injury. Movement assessments have yet to be consistently integrated into the clinical decision-making process because of the lack of understanding of how these tools further our knowledge of appropriate return-to-sport criteria. The results of this study suggest that return-to-sport decision making based on clinical examination and surgeon opinion alone does not differentiate patients with poor levels of neuromuscular function that place athletes at an elevated risk for future injury. The results of the study suggests that many patients who meet traditional clinical criteria for return to sport including time since surgery, effusion, range of motion, graft laxity, and quadriceps strength still have functional and neuromuscular deficits that may put them at risk for further lower extremity injury. Poor neuromuscular control and biomechanical aberrancies have been implicated in ACL rupture as well as retears.13,16,17,32,38 Based on the results of this study, there is no significant difference in scoring on the FMS test between the patients who were clinically cleared for return to sporting activities without restriction and those who were not. Scores for both the cleared (12.73 6 2.9) and not-cleared group (12.82 6 2.7) are below the injury predictive threshold of 14 and well below the normative value of 15.7 6 1.9 published by Schneiders et al36 in uninjured populations. This comparison between prior research and the current study would suggest that at the time of testing, these athletes were deficient in dynamic control and therefore at an increased risk for injury.19,36 Similarly, there was no statistical difference between the YBT-LQ composite or individual reach direction distances between patients who were cleared to return to sport and those who were not cleared. However, performance on the YBT-LQ displayed low competency and reach asymmetry levels that were below normative levels as well as below established cut points (\94.0% leg length) that have been previously associated with an elevated risk of injury.7,35 The observation of reach asymmetry across both groups may suggest that movement deficits may have existed before the initial ACL rupture and thus may have been associated with the initial injury. The lack of difference in FMS and YBT-LQ outcomes between the 2 groups suggests that a routine clinical examination may not pick up neuromuscular control deficits, which may be compensated for and nonobserved during clinical evaluation but which may be contributing to an abnormal movement pattern, placing the limb at risk for reinjury. With high retear and reinjury rates and no ideal postoperative assessment tool as yet, there is room for continued investigation into options to create an objective guide for safe return to sport. A recent systematic review concluded that of the 264 articles reviewed, only 13% included an objectively measured criterion other than postoperative time as part of their return-to-sport guidelines.3 The most commonly reported criteria included some combination of
muscle strength analysis via isokinetic testing or evaluation of quadriceps atrophy, knee effusion, range of motion, single-legged hop testing, stability on the Lachman test, pivot shift, or KT-1000 arthrometer (MEDmetric), and validated questionnaires such as Knee Injury and Osteoarthritis Outcome Score or Knee Self Efficacy Score.3 Recently, it was shown that patients who were cleared for return to sports based on postoperative time and clinical criteria had persistent limb asymmetry in single-legged hop height and vertical ground-reaction forces compared with age-matched controls.28 In addition, in another recent article, patients who did not pass return-to-sport criteria (time greater than 6 months, isokinetic quadriceps strength testing, single-legged hop, crossover hop, triple hop, and timed hop as well as self-reported outcomes measures) had significantly different gait behaviors detectable on force plates and with 3-dimensional motion analysis.13 Other biomechanical studies have evaluated posture and strength32 and valgus loading17 during jump landing for prediction of injury or reinjury of the ACL. These studies found significant differences in neuromuscular control causing altered knee position during landing in patients who suffered an ACL injury, further strengthening the idea of postural stability, flexibility, and neuromuscular control as key components of full rehabilitation after ACL reconstruction. These previous results are similar to what is being reported in the current study, which indicates that many patients who were clinically cleared for return to sports still lack complete motor control and coordination. An advantage of the functional testing used in the current study is that this functional assessment is inexpensive and can be used in any office setting compared with highly technical equipment needed for biomechanical analysis through force plates and 3-dimensional motion capture. To date, no battery of tests has been shown to be effective in reducing future injury rates after ACL reconstruction, which makes this an area of high interest.30 The present study is the first to our knowledge to use the FMS and YBT-LQ tests to detect deficits in neuromuscular control and side-to-side asymmetries after ACL reconstruction as an adjunct to traditional clinical examinations and testing. The current study does have limitations. Although the clinical and rehabilitation protocols were the same across the study population, there were three surgeons involved in performing surgery and clinical examinations, several graft types were used, and multiple physical therapists supervised therapy. Thus, there was heterogeneity in the subjective nature of the decision making pre-, intra-, and postoperatively because of surgeon bias as well as differences in expectations attributed to age, comorbidities, and sport participation. In addition, although the data were collected prospectively according to our department’s protocol, the retrospective nature of the data review carries some inherent bias. An additional limitation is the differences in age between the cleared and noncleared group, which may be resolved in a larger scale study. It has been suggested that younger patients recover more quickly than older patients do, and thus the fact that the cleared group was older than the noncleared group would tend to
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be in contrast to current clinical impression. The difference in age may also be attributed to different clearing standards associated with an older patient population who may be returning to a less intense level of competition/ activity. While both populations were considered to be young adults in nature and thus the difference in biologic age likely has minimal effect on the tissue-healing abilities associated with recovery time, it would be expected that the activity level differences between these age groups would be associated with different levels of reinjury risk and thus would be an important factor in return-to-play decision making.38 Finally, this initial study would have benefitted from a larger sample size to normalize some of the descriptive statistics associated with the patient samples. Future directions of this work will include following this cohort for a longer period of time to better examine reinjury rates and determine if the FMS and YBT-LQ normative values correlate with risk of reinjury in patients after ACL reconstruction. Ultimately, we aim to determine criteria using both clinical and functional testing values to develop an ideal set of return-to-sports criteria.
CONCLUSION There was no difference in FMS or YBT-LQ test scores in patients after ACL reconstruction who were clinically deemed appropriate for return to unrestricted activity based on clinical criteria. The use of the FMS and YBTLQ allow for additional tools that could be used quickly and efficiently in an office setting to give more information on the movement abilities of each patient.
A Video Supplement for this article is available in the online version or at http://ajsm.sagepub.com/supplemental.
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